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Old 05-02-2008, 11:05 AM   #751
Reposado1800
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Location: 5th and Main
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Yamaha did some strange Voodoo on the bike in its stock configuration. The intake snorkle is a big cork on the intake side. The exhaust has a tiny hole down inside the muffler for spent gas to exit through. It is plugged going in and plugged going out. The motor was tuned to work fine with this lame configuration. Things go weird when it bcomes uncorked and the wieredest thing of all is having to go leaner on the main jet.
My suggestion for anyone with a completely stock bike is to only adjust the air screw and do the pilot jet. Leave in the snorkle and do not mod the muffler.
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Old 05-02-2008, 03:45 PM   #752
mini_thumper
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I still want to try finding a different needle or needle jet. It maybe a waste of time but I have already invested so much time in it I hate to leave any stone unturned.

It is so close to running really good. And as I mentioned, I did having it running pretty well with 3 shims and a 140 main - with the side covered removed. So I think with the correct combination it can get more fuel??
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Old 05-02-2008, 06:56 PM   #753
norvegicus
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Quote:
Originally Posted by rdnakx250
...
I am tempted to install a stainless steel screen over the outgoing side of the carb as it plugs into the intake manifold to see if it would aid in atomizing a richer mixture.
A screen will make it worse, not better. Fuel mist will condense on the screen and then blow off it in drops. Also a screen cuts down on airflow a lot more than you might think.
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Old 05-02-2008, 08:44 PM   #754
Reposado1800
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Thanks for the advice. I won't go that route.
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Old 05-02-2008, 09:41 PM   #755
Benjava
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" the wieredest thing of all is having to go leaner on the main jet."

It seems weird and counter intuitive but it's actually normal. On all of the bikes I have jetted using a dynomometer with a/f the stock main is to big after the intake and exhaust is opened up. It's the mid range that needs to get richer as in shims.
I can explain it but It's long and I type slow.

I believe all jetting done without a dyno is a lucky guess at best.
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Old 05-02-2008, 10:01 PM   #756
RichBeBe
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Quote:
Originally Posted by NJ-Bill
Ironically, I ordered new tires last night. After doing much research on xt225.com, here is what I ordered from Motorcycle Superstore. Because I spent over $100, they ship free.
I just picked up an XT and plan on riding it in the Barrens as well as using it for commuting. Have you put the tires on yet? How do you like the Pirelli? I was going to buy a D606 but I am all ears if you like it more
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Old 05-02-2008, 10:24 PM   #757
RichBeBe
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Quote:
Originally Posted by NJ-Bill
The new tires go on tomorrow and I am riding the Pine Barrens on Sunday... stay tuned.
Thanks, also let me know what you think of their on-road manners if you can. Thanks
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Old 05-02-2008, 11:40 PM   #758
mini_thumper
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Quote:
Originally Posted by Benjava
" the wieredest thing of all is having to go leaner on the main jet."

It seems weird and counter intuitive but it's actually normal. On all of the bikes I have jetted using a dynomometer with a/f the stock main is to big after the intake and exhaust is opened up. It's the mid range that needs to get richer as in shims.
I can explain it but It's long and I type slow.

I believe all jetting done without a dyno is a lucky guess at best.
What is A/F??

I would really like to figure this out. Please give me your thoughts in an abbreviated form.

Do you think a richer needle or needle jet will help?

Thanks
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Old 05-03-2008, 07:22 AM   #759
zomby woof
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Quote:
Things go weird when it bcomes uncorked and the wieredest thing of all is having to go leaner on the main jet.
My suggestion for anyone with a completely stock bike is to only adjust the air screw and do the pilot jet. Leave in the snorkle and do not mod the muffler.
Its a pretty common occurrence for these small 4 strokes to draw in too much fuel in the higher RPM's, at WOT, especially if you have them uncorked.
The fuel doesn't atomize well, and the result is that the motor starts to break up.
Most people mistake this for a rev limiter.
Once you start to remove restrictions, airflow increases, and it often draws more fuel. This is why you need to jet down.
You never really know which way its gong to go until you try it.
Last year, I put a perf. cam in a DR, and had to go way lean in the midrange, but he main jet was fine.
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Old 05-03-2008, 10:03 AM   #760
braindead0
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Quote:
Originally Posted by mini_thumper
What is A/F??
Air/Fuel usually referring to the ratio of air to fuel.

The only mods I've done to my wifes it to uncork the exhaust, shim the needle .020" and turn out the pilot screw 2.5turns. Runs like a top with that. If/when she decides she wants more power, we'll probably get her a DRZ400 or something along those lines.
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Old 05-03-2008, 10:50 AM   #761
mini_thumper
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I did go down the path thinking it was hitting a rev limiter but eventually I ruled that out.

It is just so odd how differently it reacts to the airbox changes. All those changes (6 holes in the air box, a Uni Filter, snorkle cut down and the exhaust drilled) it is still the same jetting as stock other than 1 little shim??

I might try to take the shim out and go bigger on the main??

Is everyone else's plug still white?
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Old 05-03-2008, 05:58 PM   #762
Hatch
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ok, anyone ever lose their keys? mine rattled out while I was ridin yesterday, and I dont have a spare. went to the local yamaha dealer and they took down the code on the tumbler and made a key, but it didnt work. any suggestions?
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Old 05-05-2008, 02:36 PM   #763
andrewgore
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A lot of good info here. I can't say I've got an xt225, but basically the same thing. I picked up a Zongshen Sierra 200. At first I thought it was one of the honda xr200 knock0ffs, but after much more reading, and stumbling upon this website\asstd. others in search of ways of getting a little more giddyup out of the bike. I can say about the bike that so far, the only downside I've found is that it has a 15" rear wheel. Quite lame for off-road tire selection, but from what I've found here, it looks as though an xt225 wheel or a ttr230 wheel will bolt right up. It's worth the low cost risk to pick one up off ebay. Anyways, thanks for the the wealth of information on here. It's a small little bike, but man it's great for getting to work, and messing around on some local roads. Unfortunately for the other unlucky northern illinois folk....the roads here are all flat, and not much options for off-road riding. :) if anyone has any input on this bike, or other things that appear compatible, let me know...I'm up for trying anything.

Andrew

ps....my bike was only 2k brand new out the door (tax\title\license), and even has a 1 year warranty. Can't beat it!
pps. forgot link to pics of the bike! http://andrewgore.net/?page_id=31
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Old 05-05-2008, 09:15 PM   #764
Reposado1800
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On Saturday I did a 160 mile round trip and got 72 mpg mostly riding at 70 mph. The custom oil cooler works very well. After pulling off the highway I reached down to touch the inlet line and it was hot enough I had to pull my finger away, on the exit line I could hold my finger on it and not get burned. Not scientific but it is working good. I hope that guy on TW200 forum makes more of these adapters. They are dope.
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Old 05-06-2008, 05:25 AM   #765
RichBeBe
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Quote:
Originally Posted by NJ-Bill
The verdict is in. I actually rode more asphalt than normal on yesterday's ride... and a ton of deep sand. The new tire combo was fantastic. It dramatically changed the bike's handling characteristics. It is so much easier to ride in the dirt.... front tracks better and the rear has so much more traction. The asphalt section of the ride was uneventful, which is a positive in my book. There were no surprises and minimal buzz from the virgin knobbies. I am very pleased with my choice.
Thanks I rode CyberDos's XT with a Trackmaster rear, D606 front in the Barrens and it was awesome. Just debating between the Pirelli versus Dunlop. Thanks for the road feedback.
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